If carbon-dioxide present in the atmosphere is only 0.03% how can it causes Global warming?
Due to certain human activities like deforestation, burning of fossil fuels, industrial emission of gases there has been an increase in concentration of atmospheric CO2 from 0.03 % to 0.038 and this little change in its concentration is enough to cause increase temperature or warm up the climate . Because if not than our our earth would have been very much colder.
Thus little change in conc of CO2 is extremely powerful to raise the temperature of earth's climate considerably.
And yet the researches are going on in many countries on this effect of global warming due to CO2.